RELATIONSHIP BETWEEN SERUM HEAT-STABLE NEUTROPHIL CHEMOTACTIC ACTIVITY DURING EARLY AIRWAY REACTION TO ALLERGEN AND THE PATTERN OF AIRWAY RESPONSE (EARLY VERSUS LATE REACTIONS) IN ASTHMATIC SUBJECTS

In order to evaluate the relationship between allergen-induced heat-st able neutrophil chemotactic activity (HS-NCA) release during early ast hmatic reaction (EAR) and the presence of a late asthmatic reaction (L AR), serum KS-NCA was measured at three serum dilutions (1:5, 1:40, 1: 200) during EAR induced by allergen in 26 atopic asthmatics, 13 with i solated EAR and 13 with EAR followed by LAR. HS-NCA was measured using a 48-well microchamber with 5-mu m-pore-size nitrocellulose filters, using isolated neutrophils from healthy donors and the leading front t echnique. Subjects with LAR developed EAR after inhalation of a lower dose of allergen than subjects with isolated EAR. Increase in serum HS -NCA during EAR was significantly higher in subjects with isolated EAR than in subjects with EAR plus LAR at the 1:5 dilution, while it was significantly higher in subjects with EAR plus LAR than in the subject s with isolated EAR at the 1:200 dilution; the 1:40 dilution gave simi lar results in both groups. Changes in serum HS-NCA during EAR signifi cantly correlated with the maximum decrease in forced expiratory volum e in 1 s (FEV1) during LAR: a higher decrease in FEV1 during LAR was a ssociated with a lower increase in HS-NCA at the 1:5 dilution (Spearma n's rho = 0.43, p = 0.03), and with a higher increase in NCA at the 1: 200 dilution (Spearman's rho = -0.46, p = 0.02). These results can be explained by the 'high-dose-inhibition' phenomenon. Assuming that HS-N CA is associated with mast cell degranulation in the airways after all ergen challenge, these findings demonstrate that higher mast cell acti vation during EAR is present in subjects with a subsequent LAR than in subjects with isolated EAR.